Support means for cathode ray tube gun structure



S. H. BORMAN Oct. 4, 1966 SUPPORT MEANS FOR CATHODE RAY TUBE GUN STRUCTURE v Filed Oct. 25, 1,961.

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/ 1 f f 1 f f INVENTOR. .5/1 MI/E H. 50K/VAN United States Patent O 3,277,328 SUPPORT MEANS FOR CATHODE RAY TUBE GUN STRUCTURE Samuel H. Borman, Willow Grove, Pa., assignor, by

mesne assignments, to Philco Corporation, Philadelphia, Pa., a corporation of Delaware Filed Oct. 23, 1961, Ser. No. 146,952 2 Claims. (Cl. 313-82) This invention relates genera-lly to -cathode ray tubes, and more particularly to improvements in cathode ray tube gun structure. The invention, while applicable in its broader aspect to cathode ray tubes generally, will be described and illustrated in relation to constricted neck tubes, where it has special utility.

In the assembly of electron guns for cathode ray tubes :and the like, it has been the practice to bind the metal electrode elements by insulators which are viscous at the time of application, but which later solid-ify into rigid insulating members. Attachment, or binding, of the metal parts to the insulating members is facilitated by means of axially aligned studs or brackets attached to and extending radially from the metal part-s. The insulating members have comprised parallelly disposed glass rods heated to a suitable viscous state and applied individually to one radially extending axially aligned set of studs at a time. In the assembly of electrode elements of gun structure comprising, for example, a plurality of glass rods, the rods must be heated individually, in succession, in order to complete the assembly. In a high production volume of gun structures in which such electrode assemblies are utilized, a separate heating and cooling operation in attaching each insulator represents a considerable time factor in the overall product-ion rate.

Also there has been increased demand for more compact television picture tubes of large fluorescent screen area. Efforts toward -achieving compactness by reducing tube depth have involved increasing the electron beam deflection angle and reducing the length and diameter of the tube neck within which the electron gun is disposed. As to reduction of the dimensions of the neck tube, dithculties have been encountered in that glass rod supported gun structure does not lend itself to a reduction in diameter to the extent required. The present invention is directed primarily to overcoming these difficulties.

It is a general objective of the invention to provide means facilitating assembly of the elements of electron gun structure in a minimum space. It is a further general -objective of the invention to provide a novel electron gun structure perm-itting reduction in the dimensions of the neck of a cathode ray tube through a unique arrangement of insulating and support structure,

The invention is featured by the provision of an electron gun which is very simple yet very rigid in construction. It is an additional feature of the invention that it eliminates heating and cooling of insulating support means which often results in distortion and misalignment of the elements of the gun structure, constituting a major problem.

In accordance with the foregoing and other objectives, the invention is characterized by provision of a hollow ceramic cylinder in which the aligned metal electrode elements of the gun structure are disposed and held in radial spaced rela-tion with respect to the cylinder by stud elements which extend through transversely extending apertures provided in the ceramic cylinder, are frictionally retained in the apertures, and are attached to the electrode elements. When two or more portions of each electrode element are secured by this method permanent yaccurate alignment thereof is achieved by utilizing an annular space of but 1A; inch thickness or less.

It is a feature of this invention, by way of compariice son, that whereas electron gun structure held together by glassrods has required a l and 14a inch diameter glass tube neck, the present invention permits use of a glass tube neck of but 3A inch diameter.

The reduction in diameter afforded by the invention is inva-luable when it is considered that it meets the requirements that the `turns of the coils forming the deflection yoke should be so disposed and congured as to be in close proximity to the electrons of the scanning beam. This arrangement insures production of the highest possible magnetic eld intensity and hence -application of a maximum deilecting force to the beam of electrons emitted from the gun structure. In other words the invention enhances operation of the cathode ray tube because the deflection yoke is able to operate with maxirnum eiciency. Moreover, advantages stemming from the invention will be more fully appreciated when considered in light of the fact that it has been the practice, in -ceramic supported gun structure, closely to nest the metal electrode elements within a ceramic insulator, with deleter-ious effects on operation of such a gun structure. By spacing the electrode elements from the inner walls of the ceramic insulator in accordance with the invention, deleterious effect-s encountered due to a characteristic static charge buildup on surfaces of a ceramic insulator are minimized. Also, spacing the electrode elements from the ceramic insulator support enhances resistance to highvoltage breakdown, also characteristic of known ceramic support structure.

The foregoing as well as other objects and advantages of the invention will best be understood upon consideration of the following description taken in light of the accompanying drawing in which:

FIGURE 1 is an elevational showing, partly in section and with parts broken away, of a cathode ray tube embodying gun structure .made in accordance with the invention; and

FIGURE 2 is a somewhat enlarged fragmentary showing, partly in section, of the gun structure shown in FIG- URE l and illustrating techniques utilized in assembling the same.

With more particular reference to the drawing, and rst to FIGURE l, cathode ray tube 10 is provided with a generally cylindrical' neck portion 11 having la flat end portion 12 through which extend electrically conductive terminal pins 13.

Gun structure 14 is disposed within neck lportion 11 and is supported from the left and right hand ones of pins 13. The gun structure comprises a cathode heater 15 disposed within an indirectly heated cathode sleeve 16 over the end of which is disposed electron emissive material 20. Sleeve 16 is spaced relative to and supported within a generally cylindrical control grid 21 by a suitable insulative disk 17 and a resilient washer 18 that frictionally engage the grid 21. The spacing of sleeve 16 is such that emissive material 20 is disposed adjacent a small opening 22 provided in -a fiat wall portion of the grid 21. Grid 21 is supported from pins 13 and cooperates with the latter to mount the gun structure within the neck port-ion 11.

In particular accordance with the present invention, a generally cylindrical sleeve 23 of electrically insulative ceramic material is disposed in such a manner that its iower end portion partially encloses control grid 21. Sleeve or cylinder 23 is supported, in the region of its lower end, by grid 21 through the agency of bracket means which comprise slender rod-like stud elements 24 that are affixed to grid 21 and extend into apertures 25 which apertures, in turn, extend through sleeve 23 generally transverse the axis thereof. Stud elements 24 frictionally engage walls of the apertures, as best seen in FIGURE 2. The stud elements are so designed as to provide a tight t within the apertures extending through the ceramic cylinder, and the match between the aperture size and stud element is therefore close to provide this tight tit.

In FIGURE 1, and in accordance with additional constructional features of gun structure 14, a generally cylindrical, apertured screen grid 26 and a ythird grid 30 are supported in spaced relation as respects one another and in concentric spaced relation with respect to ceramic sleeve 23. Finally, the anode 31 is supported in like manner by additional stud elements 24 of the bracket means, said anode 31 preferably comprising getter ring 32 and a snubber means 33 disposed in electrical contact with an electrically conductive coating (not shown) that extends over interior surface portions 34 of tube 10. Snubber means 33 is disposed and adapted to provide lateral bracing for the upper end of the gun structure. By virtue of this arrangement, stud elements 24 disposed toward either end of the gun structure provide not only a spacing function for grid element 21 and anode 31, but also provide for support of the gun structure itself. Electrical connections of the above described components are made to the pin means 13 by ri-bbon-like lead wires 37.

Additional features of the invention will be appreciated from a description of the mode of assembly, in which connection it is seen in FIGURE 2 that the apertured cylinder 23 is clamped by suitable means in a fixture (not shown) having mandrel means 40 disposed for axial alignment with the cylinder. The diameter of mandrel means 40 includes portions corresponding to the inside diameters of, for example, cylindrical elements 26 and 30, which have been positioned in the desired spaced relation as respects one another and tubular cylinder 23. With the component elements assembled according to the showing of FIGURE 2, stud elements 24 are inserted into apertures 25 as best seen in the enlarged showing afforded in FIGURE 2. It will be further appreciated that the stud elements also provide means for electrically connecting a lead wire 37 to a cylindrical gun component.

With stud elements 24 positioned as shown in FIGURE 2, mild pressure is exerted on each such element by means of a resistance welding electrode as seen -at 42, and'a suitable current is pas-sed between the element 24 and the adjacent grid element 3Q to weld the same together. Thus aiiixed to a lgrid element, the stud elements frictionally engage the walls of the apertures through which they extend and support the attached grid element in radial spaced relation to the tubular sleeve 23. Connection of a lead wire 37 to a stud element 24 is achieved by applying the welding electrode to wire 37 in the position shown in FIGURE 2 and again passing a suitable welding current between the wire and the stud element. The welding electrode and suitable circuitry are conventional, and are shown only diagrammatically in FIGURE 2 as comprising a voltage source L, an energizing switch S, transformer means T and the lead wire connections required to effect the welding current flow.

After welding the upwardly presented stud elements 24, the fixture is rotated 180 about its axis to present the remaining apertures 25 upwardly and the stud insertion and welding operation is repeated as described above. lt will be understood, however, that the invention contemplates use of any desired angular spacing or number of supporting stud elements, and is not limited to the number 4or the precise shape shown. It will further be understood that a similar operation is carried out in attaching the control grid 21 to sleeve 23, followed by making final attachment Aof the remaining gun structure elements shown in FIGURE 1.

Among the important advantages of the invention is the fact that the reduced spatial requirements of a tubular ceramic insulator are achieved without a loss in quality of performance, as is normally encountered due to ceramic static charge effects and voltage breakdowns. These latter deleterious effects are virtually eliminated due to the novel radial spacing of the metal electrodes from the tubular ce-ramic insulator.

While only a single embodiment of the invention has been described, it will be understod that it is susceptible to modification as contemplated by the scope of the appended claims.

Iclaim:

1. In a constricted neck cathode ray tube, gun structure comprising: a unitary, elongated, tubular member of ceramic material disposed concentrically of the neck of said tube, radially spaced from the latter, and having apertures extending through its wall; a plurality of tubular electrodes disposed within and concentrically of said tubular member, said electrodes being spaced along the common axis of the neck of said tube and said tubular member; a plurality of metallic rod pin means fri-ctionally secured within said apertures in said tubular member and extending therefrom into supporting engagement with said electrodes to maintain the relative axial positioning between said electrodes and the relative radial spacing between the latter and said tubular member; and terminal pin means extending through said cathode ray tube and in the direction of the axis of its neck, said pin means being electrically connected to at least one of said elect-rodes, thereby rigidly to support said gun structure.

2. In electron gun structure: a plurality of axially aligned tubular electrodes; an elongated, unitary tubular member of ceramic material within which said electrodes are disposed concentrically of said member, said tubular member being provided with apertures extending radially through the Walls thereof; and means rigidly supporting said electrodes against movements both axially of the tubular member and radially thereof, said means comprising metallic rod-like elements xedly secured to said electrodes and extending into frictional engagement with wall portions defining said apertures.

References Cited by the Examiner UNITED STATES PATENTS 3,004,183 10/1961 Levin 313-821 HERMAN KARL SAALBACH, Primary Examiner. GEORGE N. WESTBY, Examiner.

S. CHATMON, J R., Assistant Examiner. 

1. IN A CONSTRICTED NECK CATHODE RAY TUBE, GUN STRUCTURE COMPRISING: A UNITARY, ELONGATED, TUBULAR MEMBER OF CERAMIC MATERIAL DISPOSED CONCENTRICALLY OF THE NECK OF SAID TUBE, RADIALLY SPACED FROM THE LATTER, AND HAVING APERTURES EXTENDING THROUGH ITS WALL; A PLURALITY OF TUBULAR ELECTRODES DISPOSED WITHIN AND CONCENTRICALLY OF SAID TUBULAR MEMBER, SAID ELECTRODES BEING SPACED ALONG THE COMMON AXIS OF THE NECK OF SAID TUBE AND SAID TUBULAR MEMBER; A PLURALITY OF METALLIC ROD PIN MEANS FRICTIONALLY SECURED WITHIN SAID APERTURES IN SAID TUBULAR MEMBER AND EXTENDING THEREFROM INTO SUPPORTING ENGAGEMENT WITH SAID ELECTRODES TO MAINTAIN THE RELATIVE AXIAL POSITIONING BETWEEN SAID ELECTRODES AND THE RELATIVE RADIAL SPACING BETWEEN THE LATTER AND SAID TUBULAR MEMBER; AND TERMINAL PIN MEANS EXTENDING THROUGH SAID CATHODE RAY TUBE AND IN THE DIRECTION OF THE AXIS OF ITS NECK, SAID PIN MEANS BEING ELECTRICALLY CONNECTED TO AT LEAST ONE OF SAID ELECTRODES, THEREBY RIGIDLY TO SUPPORT SAID GUN STRUCTURE. 